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Spatial Distribution of Soil Erosion Sensitivity on the Tibet Plateau

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Pedosphere 2005年第4期15卷 465-472页

作者： wang Xiao-Dan zhong xiang-Hao FAN Jian-Rong Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 （China）

The Tibet Plateau, occupying the main part of Qinghai-Tibet Plateau and having an average altitude of 4 500 m, has geomorphological features that are unique in the world, with soil erosion being one of the main ecological problems. Thus the main objectives of the present research were to set up an efficient and simple way of evaluating spatial distribution of soil erosion sensitivity in the Tibet Plateau as well as the responses of soil erosion to changes of natural environmental conditions, and to indicate key regions where soil erosion should be preferentially controlled. Based on the Universal Soil Loss Equation (USLE), the study applied geographic information system (GIS) technology to develop a methodological reference framework, from which soil erosion sensitivity could be evaluated. The impact of precipitation, soil, topography and vegetation on soil erosion was divided into classes of extreme sensitivity, high sensitivity, medium sensitivity, low sensitivity and no sensitivity. With the aid of GIS, the resultant map from overlaying various factors showed that soil erosion sensitivity had great discrepancy in different parts of the region. In the southeastern part of the Tibet Plateau there were mainly three classes of sensitivity, namely, extreme, high and medium sensitivity. However, the other two classes, low and no sensitivity, were dominant in the northwestern part.

关键词： GIS soil erosion sensitivity spatial distribution Tibet Plateau

Thermal fatigue and wear of compacted graphite iron brake discs with various thermomechanical properties

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China Foundry 2024年第3期21卷 248-256页

作者： Gui-quan wang Zhuo Xu zhong-li Liu xiang Chen Yan-xiang Li School of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

The increase in payload capacity of trucks has heightened the demand for cost-effective yet high performance brake *** this work,the thermal fatigue and wear of compacted graphite iron brake discs were investigated,aiming to provide an experimental foundation for achieving a balance between their thermal and mechanical *** graphite iron brake discs with different tensile strengths,macrohardnesses,specific heat capacities and thermal diffusion coefficients were produced by changing the proportion and strength of *** peak temperature,pressure load and friction coefficient of compacted graphite iron brake discs were analyzed through inertia friction *** morphology of thermal cracks and 3D profiles of the worn surfaces were also *** is found that the thermal fatigue of compacted graphite iron discs is determined by their thermal properties.A compacted graphite iron with the highest specific heat capacity and thermal diffusion coefficient exhibits optimal thermal fatigue *** of the matrix at low temperatures significantly weakens the function of alloy strengthening in hindering the propagation of thermal *** the reduced hardness,increasing the ferrite proportion can mitigate wear loss resulting from low disc temperatures and the absence of abrasive wear.

关键词： compacted graphite iron brake disc thermomechanical properties thermal fatigue wear

Precise Planar-Twisted Molecular Engineering to Construct Semiconducting Polymers with Balanced Absorption and Quantum Yield for Efficient Phototheranostics

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Research 2024年第2期2023卷 227-238页

作者： xiang Su Zhirong Bao Wei Xie Deliang wang Ting Han Dong wang Ben zhong Tang Center for AIE Research Shenzhen Key Laboratory of Polymer Science and TechnologyGuangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China School of Biomedical and Pharmaceutical Sciences Guangdong University of TechnologyGuangzhou 510006China Department of Radiation and Medical Oncology Hubei Key Laboratory of Tumor Biological BehaviorsHubei Cancer Clinical Study CenterZhongnan Hospital of Wuhan UniversityWuhan 430071China Department of Materials Chemistry Huzhou UniversityHuzhou 313000China School of Science and Engineering Shenzhen Institute of Aggregate Science and TechnologyThe Chinese University of Hong KongShenzhenGuangdong 518172China

Semiconducting polymers(SPs)have shown great feasibility as candidates for near-infrared-II(NIR-Ⅱ)fluorescence imaging-navigated photothermal therapy due to their strong light-harvesting ability and flexible ***,the fluorescence signal of traditional SPs tends to quench in their aggregate states owing to the strongπ-πstacking,which can lead to the radiative decay pathway shutting *** address this issue,aggregation-induced emission effect has been used as a rational tactic to boost the aggregate-state fluorescence of NIR-Ⅱ*** this contribution,we developed a precise molecular engineering tactic based on the block copolymerizations that integrate planar and twisted segments into one conjugated polymer backbone,providing great flexibility in tuning the photophysical properties and photothermal conversion capacity of *** monomers featured with twisted and planar architectures,respectively,were tactfully incorporated via a ternary copolymerization approach to produce a series of new *** optimal copolymer(SP2)synchronously shows desirable absorption ability and good NIR-Ⅱquantum yield on the premise of maintaining typical aggregation-induced emission characteristics,resulting in balanced NIR-Ⅱfluorescence brightness and photothermal ***-dispersible nanoparticles fabricated from the optimal SP2 show efficient photothermal therapeutic effects both in vitro and in *** in vivo investigation reveals the distinguished NIR-Ⅱfluorescence imaging performance of SP2 nanoparticles and their photothermal ablation toward tumor with prominent tumor accumulation ability and excellent biocompatibility.

关键词： property conducting twisted

Grating-free autofocus for single-pixel microscopic imaging

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Photonics Research 2024年第6期12卷 1313-1321页

作者： GUAN wang HUAXIA DENG YU CAI MENGCHAO MA xiang zhong XINGLONG GONG CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230027China School of Instrument Science and Opto-electronics Engineering Hefei University of TechnologyHefei 230009China

As a computational technology,single-pixel microscopic imaging(SPMI)transfers the target’s spatial information into a temporal *** traditional focusing method of imaging before evaluation is not applicable to the SPMI *** propose a grating-free autofocus strategy derived from the physical mechanism of optical *** the amplitude information of just one high-frequency point in the spectrum is all that is needed to achieve fast autofocus with the SPMI ***,only four patterns need to be cyclically projected,enabling efficient localization of the focal plane based on the measurement *** demonstrate SPMI autofocus experiments at micrometer and even nanometer depths of *** proposed method can be extended to achieve SMPI autofocus with invisible optical pattern illumination.

关键词： optical system illumination

A Spatialization-based Method for Checking and Updating Metadata

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Journal of China University of Mining and Technology 2005年第3期15卷 183-186页

作者： ZHAO Ren-liang wang Dong-hua SHI Li-hong ZHANG Bei-fei SHANG Yao-ling wang zhong-xiang National Geomatics Center of China Beijing 100044 China Chinese Academy of Surveying and Mapping Beijing 100039 China

In this paper the application of spatialization technology on metadata quality check and updating was dis-cussed. A new method based on spatialization was proposed for checking and updating metadata to overcome the defi-ciency of text based methods with the powerful functions of spatial query and analysis provided by GIS software. Thismethod employs the technology of spatialization to transform metadata into a coordinate space and the functions ofspatial analysis in GIS to check and update spatial metadata in a visual environment. The basic principle and technicalflow of this method were explained in detail, and an example of implementation using ArcMap of GIS software wasillustrated with a metadata set of digital raster maps. The result shows the new method with the support of interactionof graph and text is much more intuitive and convenient than the ordinary text based method, and can fully utilize thefunctions of GIS spatial query and analysis with more accuracy and efficiency.

关键词： metadata data quality checking spatialization spatial analysis

Miniaturized power detection module operating in millimeter wave band

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Journal of Electronic Science and Technology 2024年第2期22卷 69-76页

作者： xiang Zhou Zhi-Yong zhong School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China

The miniaturized broadband detection module can be embedded into the microwave application system such as the front end of the transmitter to detect the power or other parameters in real *** is highly prospective in military and scientific *** this paper,a broadband power detection module operating at 26.5 GHz-40.0 GHz is designed by using low-barrier Schottky diode as the detector and a comparator for threshold *** module can dynamically detect the power range between-10 dBm and 10 dBm with the detection accuracy of 0.1 ***,the temperature compensation circuit is also applied to improve the measurement *** a result,the resulted error low to±1 dB in the temperature range of -55℃ to +85℃ is *** designed module is encapsulated by a Kovar alloy with a small volume of 9 mm×6 mm×3 *** endows the designed module the advantages of small size,easy integration,and low cost,and even it is applicable to high-reliability environments such as satellites.

关键词： Diode Miniaturization Power detection Temperature compensation

Identifying Three New AGNs among Fermi Unidentified Gigaelectronvolt Sources

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Research in Astronomy and Astrophysics 2024年第7期24卷 257-267页

作者： Shun-Hao Ji zhong-xiang wang Qiang-Meng Huang Ruo-Heng Yang Department of Astronomy School of Physics and AstronomyYunnan UniversityKunming 650091China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

We report our identification of three gigaelectronvoltγ-ray sources,4FGL J0502.6+0036,4FGL J1055.9+6507,and 4FGL J1708.2+5519,as Active Galactic Nuclei(AGNs).They are listed in the latest Fermi-Large Area Telescope source catalog as unidentified *** find that the sources all showedγ-ray flux variations in recent *** different survey catalogs,we are able to find a radio source within the error circle of each source's *** analysis of optical sources in the fields allows us to determine the optical counterparts,which showed similar variation patterns to those seen inγ-*** optical counterparts have reported redshifts of 0.6,1.5,and 2.3,respectively,estimated from photometric *** addition,we also obtain an X-ray spectrum of 4FGL J0502.6+0036 and a flux upper limit on the X-ray emission of 4FGL J1055.9+6507 by analyzing the archival *** broadband spectral energy distributions of the three sources from radio toγ-rays are *** mainly theγ-ray properties of the three sources with those of different sub-classes of AGNs,we tentatively identify them as *** optical spectroscopy is highly warranted for obtaining their spectral features and thus verifying the identification.

关键词： gamma-rays galaxies-(galaxies)BL Lacertae objects general-(galaxies)quasars general

Spark plasma sintering of tungsten-based WTaVCr refractory high entropy alloys for nuclear fusion applications

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 146-154页

作者： Yongchul Yoo xiang Zhang Fei wang Xin Chen Xing-zhong Li Michael Nastasi Bai Cui Department of Mechanical&Materials Engineering University of Nebraska-LincolnLincolnNE 68588USA Nebraska Center for Materials and Nanoscience University of Nebraska-LincolnLincolnNE 68588USA Department of Nuclear Engineering Texas A&M UniversityCollege StationTX 77843USA

W-based WTaVCr refractory high entropy alloys (RHEA) may be novel and promising candidate materials for plasma facing components in the first wall and diverter in fusion reactors. This alloy has been developed by a powder metallurgy process combining mechanical alloying and spark plasma sintering (SPS). The SPSed samples contained two phases, in which the matrix is RHEA with a body-centered cubic structure, while the oxide phase was most likely Ta2VO6through a combined analysis of X-ray diffraction (XRD),energy-dispersive spectroscopy (EDS), and selected area electron diffraction (SAED). The higher oxygen affinity of Ta and V may explain the preferential formation of their oxide phases based on thermodynamic calculations. Electron backscatter diffraction (EBSD) revealed an average grain size of 6.2μm. WTaVCr RHEA showed a peak compressive strength of 2997 MPa at room temperature and much higher micro-and nano-hardness than W and other W-based RHEAs in the literature. Their high Rockwell hardness can be retained to at least 1000°C.

关键词： refractory high entropy alloy plasma-facing material fusion reactor spark plasma sintering

An Innovative Coupled Common-Node Discrete Element Method-Smoothed Particle Hydrodynamics Model Developed with LS-DYNA and Its Applications

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China Ocean Engineering 2024年第3期38卷 467-482页

作者： SHEN zhong-xiang wang Wen-qing XU Cheng-yue LUO Jia-xin LIU Ren-wei School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 210098China

In this study,a common-node DEM-SPH coupling model based on the shared node method is proposed,and a fluid–structure coupling method using the common-node discrete element method-smoothed particle hydrodynamics(DS-SPH)method is developed using LS-DYNA *** DEM and SPH are established on the same node to create common-node DEM-SPH particles,allowing for fluid–structure *** simulations of various scenarios,including water entry of a rigid sphere,dam-break propagation over wet beds,impact on an ice plate floating on water and ice accumulation on offshore structures,are *** interaction between DS particles and SPH fluid and the crack generation mechanism and expansion characteristics of the ice plate under the interaction of structure and fluid are also *** results are compared with available data to verify the proposed coupling ***,the simulation results demonstrated that controlling the cutoff pressure of internal SPH particles could effectively control particle splashing during ice crushing failure.

关键词： common-node DEM-SPH fluid-structure interaction discrete element method smoothed particle hydrodynamics